Bring it back, bring it back, don't take it away from me - the sorting receptor RER1

Area of Science:

• Cell Biology
• Molecular Biology
• Protein Trafficking

Background:

• The sorting receptor RER1 localizes to the intermediate compartment and cis-Golgi.
• RER1 retrieves escaped proteins and unassembled subunits back to the endoplasmic reticulum (ER).
• Ligand recognition by RER1 occurs via binding motifs within its transmembrane domains.

Purpose of the Study:

• To review the cell biology of RER1 across different model organisms.
• To discuss the proposed functions and controversial roles of RER1, particularly in the brain.
• To provide an outlook on future research directions for RER1.

Main Methods:

• Literature review of RER1 research in yeast, mammalian cells, and mouse models.
• Analysis of RER1's localization, function, and substrate recognition mechanisms.
• Discussion of in vivo studies and emerging roles of RER1.

Main Results:

• RER1 plays a crucial role in retaining ER-resident proteins and unassembled subunits within the ER.
• Mechanisms of RER1-dependent retrieval are well-established in yeast and increasingly understood in mammals.
• In vivo studies are beginning to elucidate the physiological importance of RER1.

Conclusions:

• RER1 is essential for maintaining ER homeostasis and ensuring the proper assembly of protein complexes.
• Further research is needed to fully understand RER1's diverse roles and its implications in various cellular processes and diseases.
• Investigating RER1 in mammalian systems and mouse models is key to uncovering its broader biological significance.